Brake control apparatus



Dec. 4, 1956 c. DOOLITTLE 2,772,904

BRAKE CONTROL APPARATUS Filed Dec. 29, 1954 2 Sheets-Sheet J INVENTOR.

, ChaYles Doolittle fwd 9221 ATTORNEY Dec. 4, 1956 c. DOOLITTLE 2,772,904

BRAKE CONTROL'APPARATUS 2,772,904 Patented Dee. V4, 1956 v 2,712,904 BRAKE CONTROL APPARATUS A Charles Doolittle, Pittsburgh, Pa., assignor to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania I Application December 29, 1954, Serial N0. 478,311. l

9 Claims. 11. 291-2 "This invention relates to brake control apparatus for vehicles, particularly automotivevehicles such as trucks,

service life, as well Another object of my invention is to provide an antiwheel-slide control apparatus of the typeindicated in the foregoing object, including a control device of the rotary inertia Itype, characterized by a novel construction and arrangement which combines simplicity; and ruggedness of construction in a manner to provide long trouble free as a reasonably economic cost 10f manufacture. i

Another object of' my invention is to provide, in an anti-wheel-slide control apparatus ofthe type indicated in the foregoing objects, a simplified valve arrangement for simultaneously controlling the brakes and sandinglj truck trailers and buses, and especially to control appa- L:

ratus for preventingi locking, that is sliding, of vehicle wheels resulting from operator-controlled brake applications, by automatically controlling release and rea'pplication of the wheel brakes.

Various devices and types of apparatus have heretofore been proposed for preventing the sliding of the wheels of automotive vehicles, that is the draggingof the wheels on the road surface in a locked state, caused by excessive brake application, as effected by the operator, in relation tothe adhesion of the wheel tires to the road surface. It

is especially desirable and necessary that sliding of wheels on trucks, buses and truck trailers be prevented in view of the great masses and weights involved. Sliding,ior

' or anti-wheel-skidding control device for automotive Other objects and advantages of my invention will be come apparent in the following more detailed description thereof when read in conjunction with the accompanying drawing wherein: i i Fig. is a horizontal diagrammatic view, outline; showing'a brake control apparatus embodying the inven tion as it maybe applied to a truclr-trailer,

d Fig. 2 is an enlarged elevational'view, partly in section and partly 'in outline, showing details. of the novel anti-i wheel-slide controller device and associated control valve device, included in the apparatus shown in Fig. 1, and

Fig.1 3 is an enlarged fragmentarysectional view taken along linej3 3 iof Fig. 2, showing a detail of a component part of the anti-wheelslide controller device shown in Description As shown invthe' drawingsfthe numerall designates each of two sts'of dual wheels" for a truck-trailer, which wheels may be the front and rear wheels of a full trailer vehicles has not been commercially feasible because of 5 the complexity of'construction of the proposed devices, ;the difficulties of application thereof to existing trucks, jbuses and truck trailers, and also because of the excessive n cost of'the device and of its installation.

According to my present invention I have devised a gnovel control device, of the rotary inertia type, sensitive ;,.,to acceleration and deceleration of automotiveiveliicl e wheel, for detecting the slipping of the wheel at the iinstant it begins to decelerate to a locked condition,

{together with apparatus whereby said control device automaticallyf r eleases the operator-applied brake application -.and thenfreapplies the brake, so as to prevent actual ilocking ,of'thef wheel or wheels. It will be understood zvtha t the term: slip and its variants as used herein refers .to.t he rotation of the vehicle wheel at a speed different i from that corresponding to the linear speed of travel of :thehvehicle at a giveninstant. One of the features] of ;my novel control device and apparatus lies in thefac't -Itliat' it may readily be installed within the hubs of 'e'xist- A iing truck-trailer wheels in a manner so as to completely :avoid projecting beyond the outside faceof the wheel tire. Another-feature of my inventionis the relative simplicity .and ruggedness of construction which lessens the cost and reduces thenecessity for maintenance andservicing and I 'which lends itself toprolonged trouble-free service life. i

L'Another feature of my invention lies in a simplified conztrol valve arrangement whereby brake control and sandiing control are simultaneously effected under the control iof the anti-wheel-sliding control device. v

Accordingly, the principal object of my invention is of-bearings2 ona-non-rotative axle-3'. 1

The brake control apparatus embodying the invention and adapted for contr'olling-the braking ofth'e wheels 1, comprises a source of fluid under 'pressure 4, a manually operable-brake control valve device 5', abrake cylinder devicefi, an' inertia operable control: device 7, a control valve-device 8, a pilot valve'device 9, an electrically operablesanding device 10, afluid pressure'operable switch 11, and check valve devicesll. I a

The sourceof fluidunder pressure! may' be in the form of areservoir, f orexa'mple', which may be maintained chargedby a compressor not shown. p

The manually operable brake valve device 5 is located infhe 'operators cab of th'ef tra'ctor portion of the truck and is connected, as by a pipe '13, to the reservoir '4 and may bj operated either b'y 'ahand lever '14 or a; foot pedal not shown) to control'ffiow-of fluid under pressure from the 'r'eservoir 4 to pipes 15 leading 'tothe several valve devices 8, The'valvedevice 5 is preferablybf the well-khowfsdf-lapPing type which, when the operating leverl4is" operated out 'of abrake releasep-osition to an application positionin as application zone, will cause pr'oportional to the amount'which said" leverjis moved outpf its brake release' p'osit'iori intotheapplication'zoiie. ""Each' brake cylinder device 6," :arn'ed conventionally bythe axle 3, is [supplied 'withifiu'id under pressure" from the reservoir 4 through the correspondingvalve device 8 and a pipe16, in a mannerto be hereinafter described, for operatingbrake'slroes or elements (not shown) on the corresponding wheels 1. v v 7 As seenin Fig. 2, thei'ne'rtia operable control device 7 for "each Wheel comprises 'acasing having ar'r annu'lar portion 17 substantially closed at one end and'coaxial- 'ly' securediat its other endfas by a plurality of sum bolts and nuts 18 adjacent its outer periphery to'a radially extending flange 19provided at one end of a substantially QYfind r i nona Ea n a new; m l r ipr seuren h e1, eat 4 ameter hansa d. tannulanpor enz ,rAtr e endfi p flange 19, the casing portin 20 is provided with another radially extending flange by which the control device ing coaxially from the face opposite chamber 49, a uni- 7. ;isi.coaxiallyandrcmtivably secured, as ;by .a;-p1urali ty tary valve element in the form of a stem valve 51 for of, screws. 21, to the outerjace of the hubwof wheel -1. controlling communication betwen adjacent axially -.;Aefl ,whe e -23 s s ieu na ed ;hy ,.;ant ri ion beari g aligned chambers 52, 53, 54, 55 and 56'. Chamber 52 2 fi rrota eaie an r wa d yt. e9aa a ne enqing ubuis connected to pipe leading to the valve device 5, lar h lg within the casing -ppfl p l .117, @di= !t h chamber 53"is'co'h'1iected to pipe :16 'leadingto the brake ele esi endietsa s teas g- LA,mu tirfins i dselutehme cylinder device 6, chamber 54 is open to atmosphere he 2 th ieh al phas ee e; ea i 1 it in e 10 in: g'h a"port SZFchanibei SSis"connected"toa pi e end of the hub 25 for rotation thereon, the ng r at sa 58 leading to "theeheekvalve'deviee 'li ahd'the pre'ssure switch 11, while chamber 56 is operi'to charriber '52 by wayota passageway-159 provided in :the easing 48,

The stem valve 51 comprises a series of lands 60, 61, 62 alternately an d' axially "aligned'with undercut portions 63, 64, the lands being adapted, when in a certain position, for engaging certain sealing rings disposed between the cha'rr'ibers 5-2,=S3, 54, "55' and-'56,:and the undercu't iportions being adapted, when :ini a-"certain position, to allow communication between certain of said :chamb'ers, "as will be 'presently described. :Aespring 65 =:dis-,

posed in chamber "49 biases the piston-valve ISO-e51 toward'a normal position,- in which "it is :shown ..in :the drawing, and in which chamber-52 is open-to-tchamber SSQ Whi'Iechamber 54' is open-to :chamber =55. The stem "valve "51' r is operable, 1 as will be hereinafter 1 described, to a release position in which communication "between chambersgSZand"53-"and between chambers 54 and- 55 isdiSestablished; and communication between chambers 53 and 5'4' and'betWeen chambersSS and 56 is established. Chambers-49 and 52,-onopposite sides of-the-piston.' 50, a-re in'- const-antcommunication with each other through av passageway 66 in said-{ piston, with i achoke-67 vinterposed--in-=said passageway for restricting flow of 'fluid pressure from one "side of the, piston to the other.

Since -a ,detailed descriptionof -the sanding device 10 is not considered essential to an understanding of the in- ,venti'onyitlwill sufiiceto' say that'sa-id sanding device isinterposedin an electrical circuit includingthe pressure 'switch' 1 1, w hich,'when subjected to the fluid pressure (in .a manner-to her-hereinafter described), operates to close ,theci rcuit and cause the sandingdevice to drop sand in frontv of' the wheels" 1.

A timing volume 68"is interposed betweentheupressure switch ll and the check valve devices12. Uponnadmission of fluid pressure -to anyt-one of-the pipes 58 (ina gnannerto 'be later described), the check valve device :12 willgpermit saidfluid pressure to flow rapidly into the pressure switch 11 and the. timing volume 68-which :thus beeomes chargcd. H 'owever a choke 69Lin'each Qfzthecheclg valve devices ll-restricts babklflowbfflriid pressure' from the timing volume 68 and, consequently, the;pressure switch 11, sothat upon cutoff of-.fliiid pres- }sureto'pipe; 58, the pressure switch 11 reniain: closed someetime until the fiuidpressureinsaid' timing reser- {volr blows downtthrough said ch'okes thereby permitting the sanding operation to con tiri'uelfor' some. time after fiuid pres sure to pipe 58 has been cut 'oiffdep'e'nding JlPQijh'the size of said timing volume andthe .'cliokes"in s a' check: valve devices,

50,,is.,open to the conduit 46.leading,t0 the pilot valve device 9. The piston 50 has aflixed thereto and extendi 9:13 t hise'. hi -i he iiel ls o fi said tubular Y P perpendicularly to theazgis ot the spindle 30, by"rofation of said casing. The'yo ke 'SI, which may be held to the. spindle 30 by means ot'yscrew threads and; a ser'ewthreaded iimt as showniiinu-th'e'drawing,fiis provided-at points qilidistantfrbmits mid-point with a jsecond; set of l'QlLlBl'S'T34fOIT cam followers, adapted for-engaging tlie respective camxsurfacesltl, asmay beseen more clearly in Fig. 3, said followers being:disposedsvtofrotate about .theiaxisibf;saidyqke; ,A spring 35, encircling the' spindle 3.0; he -compressed :betweenla shoulder ;36 formed in the horenofzthe ,huh/35;and'axspring seat 37 -at the-Tend of said lspindleoppositethe yoke '31, for biasing said'spindle outwardly consequ y; ,1 e P SI G h r r exertedtby .the rollers 34 of said yoke 31-;onthecam surface-)9, the clutch member 26'-into frictional engage t with the ywhe l 2 r ,,.,1 A=,c e pap 3 srfit e ev e e r pen n y h t it e 'hub'25 *a qvi iirovided w th heek ve veu3 fer a s esbe her netter s le ee. Anet ne 0 t o erthe e et Q31?=3 Q1 @FQ EF f' terial andydirt f'rornflhccontrol device 7. [-A vent-41 is presided \inl he cap 0- e heiya retderi' 9'he nses sfah iy n'ea heat uh j hereinafter de ed "by inward axial movement of sp ndle: -.Ih' va e, s iee inl q houldf be understood that in order to f attain maxifliciency 'ofthe':abovc desci'ib'ed brake control ap- I paratiggfeach of thevehi'cle' wheels that is a'd 'ptd to The" b'rakdI $116516 be equipped with a "brake Yliilder '"dvie s, 'aii' ineitiabperable cemmiiid'eviee 7, s-valve opemion For purposes ofsimplicity, -;operation :iof the brake rontrolaapparatus-embodying the invention will beldcscribed-in connec-tion-with -on e set only of the wheels 1, 'which i nay' bethose :of atruck trailen' for example, it

1p s nga casm 9 .4 Q- Ili TQF ing 48 at one endo said c g nd partly by a pie sit be Similar.

device- 8, 5 pilot valvedevice 9"a"nd a saiidingb evice 1Q.

H g understoodthat-operation of the ijequipment'asso ciated'wit h' 'th'd'ther' sets b'fwheels on said trailer would Let it be assumed that the vehicle is being driven along; the highway under-normal road conditions and'-tl 1at,-;' therefore, the casing of the control device 7 is beingcorrespondingly rotated by the. wheel 1 in accordance with 'the rotative speedof said wheel. Rotation of the housingof the control device 7 drives the yoke 31 which in turn drives the clutch member 26 through the rollers 34 engaging the cam surfaces 29 of the cam portion 28. t

application position. Fluid under pressure will thus be supplied, through pipe 15, to chamber 52 of the valve device 8 to thereby momentarily cause the piston 50 and stem valve 51 to be moved to its release position until suflicient fluid pressure can be built up in chamber 49 through the passageway .66 and choke 67 on the opposite side of said piston. When fluid pressure in chamber 49, acting .in conjunction with the force of spring 65 has beenbuilt up sufiiciently to overcome fluid pressure in chamber 52 acting on the opposite side of piston 50, said piston and the stem valve 51 will be moved to its normal position, above described, it being noted that fluid pressure will also be supplied, by way of conduit 46 and passageway 45, tothe pilot valve device 9 whereby the valve 42 is retained in its seated position. It will be further notedthat in the 'normal position of the stem valve 51, chamber 55 and consequently conduit '58 leading to the pressure switch device 11 are open to atmospher'e by Way 'of chamber 54 and vent 57 in the valve 4 device '8. With the stem valve 51 in its normal position,

fiuid under pressure will be supplied by way of chambers 52 and 53, through conduit 16, to the brake cylinder device '6 to effect a brake application on the wheel 1.

Assuming that the braking force thus applied'to wheel 1 is in excess of the permissible traction between the tread of said wheel and the highway surface, said wheel, and consequently the housing of the control device7, will decele rate 'at an; abnormally rapid rate toward a non-rotating or locked condition. The flywheel 23, however, having a tendency to continue to rotate, will overrunthe housing of the control device 7 and the wheel 1 and in so doing will carry with it clutch member 26 so as to cause relative angular displacement between the cam portion 28 and the driving yoke31. This angular displacement between the cam portion 28 and the yoke 31 will cause the rollers 34, journaled on said yoke, to ride up the cam surfaces .29 until said rollers engage the uppermost point of said cam surfaces, at which point the clutch member 26 will slip on the friction face of the flywheel 23. As the rollers 34 move up the cam surfaces 29, the spindle 30 will be moved axially against the opposing force of spring 35. Suff cient axial movement of the spindle 30 is thereby produced to cause the end of said spindle to engage the stem of valve 42 and unseat said valve against the opposing force of spring 43.

- Unseating of valve 42 causes venting of chamber 49 ofthe valve device 8 by way of conduit 46, passageway 45, past the valve 42, through chamber 44, past the spindle 30, through the check valve 39 and port 41 in the cap 40. With fluid under pressure in chamber 49 of valve devices thus vented, the predominating pressure of fluid in chamber 52 on the opposite side of piston 50 resulting from the restricted rate of venting thereof through the choke 67 to chamber 49, will overcome the opposing force.

of spring 65 to thereby move the piston 50 and stem valve 51'to their release position. In the release position of the to atmosphere by way of vent 57. Venting of conduit 16 to atmosphere causes relief of fluid pressure from the,

brake cylinder device 6 and thereby'releaseof thejbralt ing force on the wheel 1, which is their free to accelerate rapidly back toward groundspeed of the vehicle. At this point it isdesired to point out that the responsive action of the control device 7' is so instantaneous that when a slipping of the wheeloccurs during a brake application,-

the brakes are released immediately before the wheel has an opportunity to attain a locked, that is sliding condition, it being understood that slipping, as herein .ap-

plied, refers to a rotating condition of the wheel in which the peripheral speed of the wheel, at a given instant, varies from linear ground speed. 6

At the time the brakes are released by operation of piston 50 and the stem valve 51 of the valve device 8,

as above described, communication between chambers. 54 and 55 is disestablished by suchoperation of said. stem valve. On the otherhand, communication between chambers 55 and 56 is established and fluid under pressure may then flow to conduit 58 and the pressure switch device 11, by way of chamber 52, passageway 59, chamber 56 and chamber 55 to cause operation of the sanding device 10 in the manner heretofore described.

With the brakes released as above described, the wheel 1 will promptly accelerate back toward and attain ground speed of the vehicle, and incident to such acceleration of the wheel the cam followers 34 will roll back down the. cam surfaces 29 to the lowermost point of said surfaces,

at which time the flywheel 23 will again be driven by the clutch member 26 in accordance with the rotation of said wheel. It will be seen that incident to acceleration of the wheel 1, and consequently of the housing of the control device 7, back toward ground speed of thevehicle, the

housing catches up to the flywheel, and since at that instant there is no slipping of the clutch member on the flywheel face, spring 35 acting through the spindle 30 and the driving yoke 31, will bias the cam followers 34 down i the cam surfaces 29 tothe lowermost pointof said surfaces. The consequent axial movement of spindle 30 away from the stem of valve 42 will permit the spring 43 from chamber 52 until the pressure in said chamber 49,-

acting in conjunction with spring 65, is suflicient to overcome the pressure on the opposite side of piston 50 in;

chamber 52 to return said piston and the stem valve 51 to their normal position. With the stern valve 51 in its normal position, fluid pressure will once again flow to conduit 15, as above described, to the brake cylinder device 6 to cause reapplication of the brakes automatically on the wheel 1. Unless the braking force acting on wheel 1 is excessive or should said wheel run into a slippery condition on the highway so that, while a brake application is in effect, said wheel tendsjto slide or lock once:

more to cause automatic release of the brakes as above described, the control of the brake apparatus will.re-

main within the discretion of the vehicle operator through; manual operation of the control valve device 5. With the stem valve 51 in its normal position, further supply:

of fluid pressure to the sanding device 10 will be terminated and the sanding action will also be terminated.

after a certain interval of time,- as above described, when the fluid pressure 'in the timingvolume 68 reduces sufliciently to efiect opening of the pressure switch 11. It Wlll thusbe seen that braking action of each set of wheels 1 and sanding is thus automatically controlled in a manner.

above described so that sliding of said wheelsis posi-f tively prevented, especially under adverse conditions of road surfaces or excessive braking, without impairment of braking effect. It will also be seen that my improved anti-wheel-slide control device willfunc tion in themanne'r described for opposite direction of rotation of the vehicle wheels.

APJ-

mination of said wheel-slip, for effecting seating of said valve, and valve means including a control chamber connected to said passageway and subjected to fluid pressure, said valve means having a normal position, in which it establishes communication through which said brake application device may be supplied with fluid pressure, and operable, upon venting of fluid pressure from said control chamber by way of said passageway, to a release position in which it establishes communication through which said brake application device is relieved of fluid pressure.

9. A brake control apparatus comprising, in combination, a brake application device operable in response to fluid pressure for eflecting a brake application on a vehicle wheel and to relief of such pressure for releasing said brake application, a sanding device operable in response to electrical energization for causing sand to be discharged immediately in front of the vehicle wheel and in response to deenergization for stopping said discharge of sand, a fluid pressure operable switch device responsive to fluid pressure and to release of fluid pressure for elfecting closing and opening, respectively, of an electrical circuit for energizing and deenergizing said sanding device, a source of fluid under pressure, conduit means providing for flow of fluid under pressure from said source to said brake application device and said switch device, first valve means interposed in said conduit means and having a control chamber charged with fluid under pressure from said conduit means, said valve means including a unitary valve element operable, in response to fluid pressure in said control chamber, to a normal position in which fluid pressure may be supplied to said brake application device and cut off from said switch device and, in response to venting of fluid pressure from said control chamber, to a release position in which'said brake application device is relieved of fluid pressure and said pressure switch is supplied with fluid pressure, timing means operable automatically for causing said switch device to maintain said circuit closed for a certain interval of time upon operation of said first valve means to its release position, said timing means including a timing volume charged with fluid under pressure supplied to said switch device and check valve means for restricting the rate at which fluid under pressure is vented from said switch device upon operation of said first valve means to its first position, second valve means for controlling venting of said control chamber, and a control device for operating said second valve means, said control device being responsive to a slipping of said wheel for operating said second valve means to cause venting of said control chamber and responsive to cessation of said wheel-slipping for operating said second valve means to a position in which venting of said control chamber is cut ofif.

References Cited in the file of this patent UNITED STATES PATENTS 2,173,938 Fitch Sept. 26, 1939 2,198,022 Aikman Apr. 23, 1940 2,198,031 Farmer Apr. 23, 1940 2,540,753 Newell Feb. 6, 1951 2,573,386 Berkoben et al. Oct. 30, 1951 2,621,885 Schmitt Dec. 16, 1952 2,656,017 Trevaskis Oct. 20, 1953 2,713,989 Bryant July 26, 1955 

